Repeater circuits



Oct. 7 1924.

' E. D. JOHNSON REYEATER CIRCUITS Filed Feb. 1. 1918 2 Sheets-Sheet 2 /n Ven/0r.' Ed@ Johnson PatentejdlOct. 7, 19.2.4.

` UNITED s'ra'ras PATENT oF EDGAR D. `JOHNSON, F EAST ORANGE,l NEW JERSEY, ASSIGNVOR TO WESTERN ELEC- TRIC COMPANY, INCORPORATED, 0F NEW YORK, N. Y., .A lCQRPORATION' F NEW YORK.

Application nled February 1,

To all whom t 'may concern.: Be it known that I, EDGAR D. JOHNSON, a

citizen of the United Sitates residing atv v East Orange, in the county oi? Essex, State 6 of New Jersey, .have invented certain newl and useful Improvements in Repeater Circuits, ofwhich the following is a, full, clear, concise, and exact description.

Thev invention relates to' repeater circuits 1U wherein a two-way transmission of currents, such as telephone current or ringing current, vis provided:

As shown in the application of Nicolson', Serial No. 223,221, filed March 18, 1918, for repeating systems, there lis provided a ref, peaterv circuit wherein it is possible to dis-f pense with, switches for reversin the repeating circuits, one of two oppositely connectedv repeater. circuits being rendered inoperative in response to current impressed on the line to permit 'the transmission of current through the 1other repeater branch 'lhe'f'iabove` Nicolson. application makesuse of vacuum tube repeaters of'the audion type and provides two 'repeater paths in parallel and am lifying currents in' opposite directions. ach line section is adapted to receive current from one of the repeater paths fortransmission in one direction, and is adapted-to transmit current tothe other path for transmission'in the other direction. In order that-there shall be no local circulation of power at the repeater station, it is necessary that the line sections, when receivin currentif'fromone repeater path, shall send t e amplifying current out upon the line without also sending the amplied current to the other? repeaterv path,

This is accomplished according to the present invention by supplying the current from each repeater path tothe other, but in hase opposition to th current supplied rom one repeater by wa of the line section to the other repeater. e opposed currents produce a resultantI zero I'effect in one bf the repeater paths, and in this way current delivered by either repeater serves to render the other inoperative, so that the amplified currents deliveredby one repeater are sent exclusively out uponthe "line, no amplified currents being transmitted'back through the l other repeater circuit to produce an objectionable local circulation lof power throiigh the repeater circuits, y

'.17- coupling the-line a to 'l '.By means of the. potential supplied to REPEATR CIRCUITS.

191,8. Serial No. 214,965.

The invention" will bey described in further detail in connection with the drawings, in which Fig, 1 illustrates a two-way repeater circuit in which anauxiliary electrode with in a vacuum'tube is energized at times to. rendera portion of the circuit inoperative; Fig.2 illustrates a cir similar to that in Fig. 1, exceptthat'no auxiliary electrode is provided, the currents having a modifiedv phase beinasupplied to the ordinary input' electrodeo )la vacuum tube; and Fig. 3 i1- lustrates the preferied form of the invention where the phase shift, is accomplished by repeatin coils.

-. In i 1, between the linesl and 2, is provide ...a repeater path 3 for transmitting l currentjin a direction from line 1 to line 2, and a repeater path 4 for transmitting cu-r- I rents in the opposite direction. 'The repeaterpath 3comprises a vacuum tube amplifier 75. 5 of the audion type which is provided with an auxiliary electrode 6.' Coupled to the output circuit of the amplifier 5 is the potentiometer 7 through which potential is supplied to the amplifier 8 of the audion type, which supplies amplified currents to l the line 2. g y

In order that repeater 1l may be rendered inoperative while' repeater 8 delivers current to line 2, the potentiometer 7 alsosupplies potential to the amplifier 9 of the Caudion type. Furthermore, the circuit 4, leading.. from potentiometer 7 to repeater 11 by way of repeater 8 and line 2, is -simulated by, the circuit from potentiometer 7 to repeater- 11 by way of re eater 9. and circuit 13. The,` neutralizing cu rents, delivered to re eater 11 over the neutralizing circuit inc uding repeater 9, will be ofthe same wave form as the currentsy fed back to re eater 11 from 2.

In order that the neutrallzing circuit may col simulate the load circuit, the repeater 9 and the repeating coil 12 coupling the output circuit of repeater 9to the input circuit of repeater 10 aresimilar respectively to the repeater 8 and re eating coil- 14 coupling 're-A peater 8 to the ine-2. Furthermore, the net work 15 which ishere shown as comrising a resistance and, a1 condenser is similar to 'theimpedance of the line 2, and the repeating coil 1,6 coupling the circuit 13 to the tube 11 v'is similar-to the repeating coil the repeater 11.. otentiometer 7, the t e tubes 8andr9`may 119 los' M adjusted so that the amplitude of the current supplied by the repeating coil 16 to the auxiliary electrode 10 is the same as the amplitude of thev current delivered to the tube 11 through the re eating coil 17. The phase of the current elivered by the neutraliring'I circuit to repeater 11 may be .made opposite Ato' the phase oil the current tion with re 430 delivered to repeater l1 by line 2, by reversing the connections of repeating coil 16, for instance. 'lhe potential supplied to the auxiliary electrode l being of the same wave form, .equal in amplitude, and opposite in phase to the current delivered by the conductor. Currents impressed on the line 2, are, however, amplified by the tube 11 to its'outputcircuit to which are coupled circuit-s similar to these'described in connecter path 3, lthe repeater being render inoperative, the amplified currents going out upon the line 1.

'lhe circuits shown inFig. 2 are the same i as those of Fig. 1, except that the currents delivered by repeating coils 16 and 17 are delivered to the same and usual input electrode 19 `of a-t'ube 20, which corresponds lto lthe repeater 11 of Fig. 1.

Fig. 3 illustrates the preferred circuit. lhis is similar to the other hgures and particularly to Fig. lexcept as to the neutralizing circuit tor c anging the phase of .the

currents to be supplied to repeater 11 (Fig.

3) to render the saine inoerative when transmitting in a direction om line' 1 to line 2;

'llhe circuit from the .points AB to repeater 11 by way et repeater 8 and coils 1d and 17 is the same as shown in Fig. 1.

'lhe currents taking this path are subject@ to the following phase changes: Assume the currents at points A'B to have zero degrees phase then the potential induced in the secondary of repeating coil 21 is 00 be hind the current in the primary. The tube 8 introduces no phase change, the current in its output circuit being in phase with the input potential.

, put' circuit of tube 8 is 90 behind Athe current at points AB. ln the secondary of coil 1d there will be induced a potential 90 behind the current in the output circuit, of

I tube Sand 180 behind the-current at points AB. The current delivered by the secondaryot coil 1d' to the line2, will be substmitially in pham with its driyingpotential ever, by reversin The current inthe outifthe resistance ot the line 2 is large m compared to its impedance'. Even though the resistance of theline 2 is not large, resulting ina phase shitt oit the current in line 2 with respect to the potential across the secondary of coil 1d, this mayfbecom- ,pensated tor in the neutralizing circuit 22.`

'lhe current in line 2 induces a potential in the secondary of coil 17 lagging 90 behind the 'current in line 2, this potential being applied to the repeater 11 and being 270 lilind the phase of the current at pointsIV 'lhe phase shift of the currents in; the neutralizing circuit 22-is as follows: By means of the resistance 23 the' amplitude of the potential applied to the electrode 10 may be regulated. The current in the primary ot Acoil 2d induces a potential tle secondary lagging by the current in the primary. lhis potential produces a current in circuit 25 which lags this induced potential by 90 since circuit 25 is highly inductive as shown. rlChe phase shift is-increased to 270by the repeating coil 20. Ayla of 270 is also experienced by the potentia ap lied to tube L11 from line 2. rll`he potentia applied to electrode 10 ma e reversed in phase, howthe connections ot any one of the coils in the circuit 22. lt, however, the exact phase lag through coils 21, 1d and 17 is diderent rom,270 as described above, it is evident that the apparatus iii neutralizing circuit 22 should be adjusted, until it produces a phase lag ot the same value, thereby producing the desired neutralization. lt is to be understood that this Ainvention is not limited tothe particular arrangement described for producing the phase lag in the neutralizing circuit, since, asis shown in the art, a phase shift may be produced by various networks of which the one described is only one type.

'lhe circuit in Fig. 3 Pis simpler, than that shownin Figs. 1 and 2, no repeater such as 0. in Fig. 1 being employed.- The neutralizing potential may be applied to the usual input electrode ol? the repeater as in Fig. 2.

While the invention is of particular advantage tor the two-way transmission of telephone currents, it is not vlimit/nl to this use but may be employed as a repeater in any circuit.. "What is claimed is: v

1. The combination of aline, a vacuum tube repeater having its output circuit etec: tively connected to tranmit current to said line, and means responsive to a current impressed on vsaid line tor supplying two currents ot substantially equal amplitudes'and opposite phases to said repeater. f

2. 'lhe 'combination ot a line,ja vacuum lllO tube device having an input circuit'and having an output circuit' etect'irely connected to sponsive to a currentimpressed on said line for supplying two currents of substantially equal amplitudes and opposite phases to said input circuit.

3. A-two-way repeater system comprising aline, repeaters of the' audion type connected in opposition inI said line, and means responsive to current impressed on said line for impressing waves of substantially equal amplitudes and Opposite phases on one of said repeaters.

l 4. The combination of two lines, two, repeaters of the audion type, .the output circuit of one of said repeaters and the input circuit of the other of said repeaters being connected to said lines and a connection between said repeaters inde endent of said lines, said connection supp ying current of substantially the same wave form as that to be repeated.

5. The combination of a line, two repeaters of the audion type, the output circuit of one of said repeaters'and the input circuit of the other of said repeaters being connected to said line, and a connection between said repeaters, said connection comprising means for supplying waves having a modified phase.

6. A two-way repeater system comprising two lines, repeaters of the audion type connected therebetween, and a plurality of phase changing circuits connecting said repeaters,

one of said repeaters being pointed for transmission therethrough in one direction vbetween said lines, and the other repeater-being pointed for transmission therethrough in the opposite direction between. saidflines.

7. A line, a repeater having an electron stream and having an output circuit effectively connected to transmit current lto said line, and means including two circuits energized from said line Afor similarly but oppositely controlling said stream for successive waves.

8. A two-way repeating system compris-v ing ,two lines, two oppositely connected repeater paths therebetween, and neutralizing circuits comprising ampliliers interconnecting said repeaters, said circuits supplying currents ofsubstantially the same wave form as the current to be repeated.

9. A line, a repeater having means for producing an electron stream, and means in cluding two circuits energized from said line for similarly but oppositely controlling said stream by a plurality of currents of alternating character and of' substantially the same frequency, said repeater having its output circuit effectively connected to transmit current to said line.

In witness whereof, I hereunto subscribe my name this 18th day ofJanuary A. D.,

EDGAR D. JOHNSON. 

